(636d) Self-Assembly of Biosynthetic Protein Polyelectrolytes and Block Copolymers

Intrinsically disordered polypeptides represent a versatile class of biomaterials, as they combine the diverse phase behavior of synthetic polymers with the tunability and biocompatibility of peptides. Here we report the biosynthesis of a panel of intrinsically disordered protein polyelectrolytes based on a disordered human protein. This endogenous protein can be engineered to systematically increase the net charge per residue, while maintaining the ability to be produced recombinantly in E. coli. This panel of anionic polypeptides can also be fused to both globular proteins and charge neutral polypeptides to create protein-based block copolymers. With this panel of biosynthetic polyelectrolytes and block copolymers, we demonstrated the ability to form polyelectrolyte complexes with a range of oppositely charged synthetic and protein biopolymers. The resulting entirely biosynthetic polyelectrolyte complexes display a rich phase behavior, transitioning between micro-phase separated nanoparticles and bulk phase separated polyelectrolyte complexes as a function of temperature. The complexes also display sensitivity to key environmental conditions, including temperature, salt concentration, and charge fraction.